/Engine/Source/Runtime/Engine/Classes/Materials/MaterialInstance.h
Sets new static parameter overrides on the instance and recompiles the static permutation resources if needed. Can be passed either a minimal parameter set (overridden parameters only) or the entire set generated byGetStaticParameterValues().
void UpdateStaticPermutation ( const [FStaticParameterSet](API\Runtime\Engine\FStaticParameterSet) & NewParameters, [FMaterialUpdateContext](API\Runtime\Engine\FMaterialUpdateContext) * MaterialUpdateContext )